The invention relates to the production of cable elements, incorporating a rigid core surrounded by a covering dielectric having helical grooves with a simple or alternating pitch, whereby optical fibers are freely placed in these grooves. The invention more particularly relates to an apparatus for placing the optical fibers in the grooves.
The simultaneous placing of an optical fiber in each of the grooves of a generally cylindrical structure of the type referred to hereinbefore and as described more particularly in French Pat. No. 2,358,666 filed by Lignes Telegraphiques et Telephoniques on Dec. 30, 1975 and French Patent Application published under No. 2,381,326 and filed by Lignes Telegraphiques et Telephoniques on Feb. 18, 1977, is ensured by means of elements constituting guides for optical fibres. These guides are elastic capillaries and by a tapered end rest on the bottom of each groove. They are maintained engaged by a light mounting support and are rotated without friction by the grooved structure, said guides forming an angle of less than 45.degree. with the movement direction. In certain productions, laying is brought about by tools fixed to a rotary core. In others, the grooved structure is translated and the laying station rotates. The use of elastic guides which penetrate the groove permit an effective guidance of the fiber without tension. The absence of friction between the guide mounting and a fixed support makes it possible for the mounting assembly of the guides and to follow any rotations of the support and irregularities in the grooves without straining the fibers, making it possible to carry out the laying operation under industrial conditions. The elasticity of the guides also makes it possible to use one and the same tool for different structures of very similar dimensions and reduce the dimensional accuracy imposed during the manufacture of the grooved structure to a value which is compatible with industrial production.
French Patent Application No. 78-05833 (publication No. 2,418,940) in the name of Lignes Telegraphiques et Telephoniques, particularly FIG. 7, describes a laying head, whose position relative to the cable support is dependent on an optical device incorporating a light source cooperating with a sensor via an optical guide traversing the laying head. The head is supported by a fixed frame via the coupling which permits rotation.